Pom pom crabs (Lybia tessellata) are an interesting and reef compatible addition to any aquarium, although, owing to their size, they make particularly good nano tank inhabitants. This crab, sometimes called a boxing crab, carries two small anemones-one in each claw-which it uses as both a defense mechanism and a means of capturing food. These peaceful animals will only grow to about an inch and do not pose a risk to any but the smallest fishes. They may drop their anemones (Bunodeopsis spp.) when molting. This Indo-Pacific omnivore may be harassed or even eaten by some predatory fishes, so it is best to introduce the pom pom crab with the lights out and very close to the rock work, where it can quickly find refuge.